CA2080174A1

CA2080174A1 - Polymer polyol dispersants from polymers containing anhydride groups

Info

Publication number: CA2080174A1
Application number: CA002080174A
Authority: CA
Inventors: John E. Hayes; Robert G. Gastinger
Original assignee: Individual
Current assignee: Lyondell Chemical Technology LP
Priority date: 1991-10-11
Filing date: 1992-10-08
Publication date: 1993-04-12
Also published as: US5358984A; JPH05214041A; EP0537028A1

Abstract

POLYMER POLYOL DISPERSANTS FROM POLYMERS CONTAINING ANHYDRIDE GROUPS Abstract of the Disclosure Dispersants that are the reaction product of polyoxyalkylene polyether polyols with polymers containing anhydride groups are discussed. These dispersants may be used in the production of polymer polyols having high styrene contents and high solids contents. The polymers containing the anhydride groups may be preformed polymers which are then reacted with the polyol, or may be formed in the polyol directly prior to esterification with the polyol to form the dispersants. Maleic anhydride and methacrylic anhydride and derivatives thereof are examples of monomers suitable for the dispersants. Polymer polyols made using these dispersants may be reacted with polyisocyanates to produce polyurethanes. :

Description

2 ~
POLYMER POLYOL DISPEE~SANTS FROM PC~LYMERS
CONTAINING ANHYDRIDE GROUPS

Field of the Invention S The invention relates to dispersants useful in the synthesis of polymer polyols, and in one aspect~ is more particularly related to dispersants prepared from a polyol and at least one polymer containing anhydride groups, followed by esterification.
Back round of the Invention Polyurethane foams, formed by the reaction of a polyisocyanate with a polyhydroxyl-containing compound in the presence of a suitable catalyst, are widely accepted as padding materials for cushions in furni-ture, automobiles and the lilce. Polyurethane foams are also used in sponges, personal care and hygiene items and as spe~ialty packaging materials.
The use of a polyol in the preparation of polyurethanes by reac-tion of the polyol wi~ a polyisocyanate h1 the presence of a catalyst and perhaps other ingredients is well known. Conventional polyols for flexible polyurethane foams, such as slab urethane foams, are usually made by the reaction of a polyhydric alcohol with an alkylene oxide, usually ethylene oxide and/or propylene oxide, to a molecular weight of about 2,000 to 5,000 and above. Polyols have been modified in many ways in attempts to improve the properties of the resulting polyure-thane, for example, by using a polymer polyol as the polyol component Conventional polyols may be used as the dispersing media or base polyol in these polymer polyols.
For example, dispersions of polymers of vinyl compounds such as styrene, acrylonitrile or a mixture of the two (abbreviated as SAN
monomers), or of polyurea polymers, such as those prepared from toluene diisocyanate (TDI) and hydrazine in conventional polyols have been included to improve the properties of the polyols, and thus, the properties of the resulting foam. Polyurethane foams with higher load bearing properties (ILD - indentation load deflection, and CFD -compression force deflection) may be produced in this manner. It would - .

. , - , . ~ .: - ., ~
~ , 2~017~
be desirable if polymer polyols could be prepared which would be stable and have low viscosities. Stability is important to the storage life of the polyols before they are used to make the polyurethane foams. The tendency of polymer polyols to undergo phase separation if they are not S stabilized is well known. Dispersants are o~ten used to help keep the polymers in the dispersion. Low viscosities and small particle sizes are also important in a good quality polyol to permit it to be pumped easily in high volume foam producing equipment.
It would further be desirable if styrene/acrylonitrile polymer 10 polyols could be synthesized which would have large SAN ratios. The substitution of styrene for acrylonitrile in these polymer polyols helps prevent discoloration during the cure of the polyurethane, and also helps improve flame retardability of ~e resultant foams. However, the stability of the polymer polyols decreases with increasing styrene to 15 acrylonitrile ratios. Viscosity and particle size are also typically ad-versely affected with high styrene contents.
The present invention involves the reaction products of homo- or copolymers containing anhydride groups with polyols. Patents are known which relate to the polymerization of monomers having anhy-20 dride groups. For example~ U.S. Pat. No. 3,085)986 teaches lowpressure molding compositions containing a mixture of a polyhydric alcohol having at least one primary hydroxyl group and a solid, linear low molecular weight copolymer of rnaleic anhydride and styrene which is cross-linlced by the alcohol. U.S. Pa~. No. 4,198,488 describes the 25 addition of an anhydride monomer to a polymer polyol composition.
The product itself is the final polymer polyol: a dispersion of solid particles, and not a preformed soluble dispersant. Stable, fluid polymer polyols made by the free radical polymerization of a monomer mixture of an a"B-ethylenically unsaturated dicarboxylic acid anhydride and a 30 copolymerizable monomer in an organic polyol medium of secondary hydroxyl terminated polyol are disclosed in IJ.S. Pat. No. 4,721,733 to Gastinger and Hayes.
Also of interest is the English abstract to Japanese Application 1004228 relating to dispersants for non-aqueous systems comprising a 35 copolymer of alkyl vinyl ether or alpha olefin, and maleic acid anhy^

2~8~17~
dride and a polyether polyol or its derivative having a number average molecular weight of 400 to 50,000. See also the English abstract to Japanese Application 1004227 which discusses dispersants in non-aqueous systems obtained by reacting polyether polyols with copolymers S of alkyl vinyl ethers or alpha olefins and maleic anhydride. Both of these latter abstracts note that the dispersant is used for dispersing inorganic or organic pigment particulates in nonaqueous media, e.g.
oily paint, oily ink, magnetic tape, etc.
To prepare polymer polyol dispersions with high styrene contents and high solids contenLs, it is the practice in the art to employ polyols which contain speci~ied and ostensibly critical amounts of induced unsaturation, as shown in U.S. Pat. Nos. 3,823,201; 4,454,255 and 4,690,956, among others. These polyols with induced unsaturation are ~ypically prepared by reacting polyols with an unsaturated monomer such as maleic anhydride or the like. U.S. Pat. No. 4,5399340 also relates to the reaction c~f polyols with monomeric anhydrides.
Stable, low viscosity polymer polyol compositions comprising a continuous phase, a disperse phase within the continuous phase, and a dispersant for enhancing the stability of the resultant polymer polyol are disclosed according to U.S. Pat. No. 5,021,506. In one embodiment, the dispersant is forrned by polymerizing at least one asrylate monomer in a polyether polyol to fonn a single phase hornogeneous liquid intermedi-ate reaction product which is transesterified to forrn a polyol polyacryl-ate dispersant.
It is well known in the art that high styrene, high solids content polymer polyols are desirable, but difficult to prepare in stable form.
There remains a need for novel dispersants for use in preparing polymer polyols that have relatively high styrene contents, but which also had good stability, small particle sizes, and low viscosity as well.
Summarv of the Invention Accordingly, it is an object of the present invention to provide a dispersant suitable for use in polymer polyols which enables the disper-sions to have high styrene contents and high solids contents.

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It is another object of this invention to provide a stable polymer polyol composition having a continuous phase, a disperse phase within the continuous phase, and a dispersant for enhancing the stability of the polymer polyol, where the dispersant employs homopolymers and/or 5 copolymers of anhydr~de monomers.
According to this invention, there is also provided a method for producing the stable polymer polyols described above, which method involves polymerizing an ethylenically unsahlrated monomer or mixture of monomers (which form the disperse phase of vinyl polymer par-10 ticles) in a blend of a polyoxyalkylene polyether polyol continuousphase and ~he dispersant. A method of stabilizing polymer polyols of this type is also presented.
Providing polyurethane compositions produced using the above described polymer polyols is also an object of this invention.
Ln carrying out these and other objects of the invention, there is provided, in one foml, a dispersant produced by polymerizing at least one anhydride monomer selected from the group consisting of Cl-C20 anhydride monomers to form a polymer followed by esterifying from about 1 to about 100 mole percent of the to~al anhydride groups in the 20 polymer with hydroxyl groups of an polyoxyalkylene polyether polyol to form the dispersant.

Dçtailed Description of the Invention, It has been discovered ~hat a new class of dispersants may be `
25 prepared which can be used to prepare high solids, high styrene, sty-rene/acrylonitrile (SAN) dispersions of polyether polyols. These new dispersants are based on the reaction product of polyols with homo- or copolymers containing anhydride groups.
The dispersants of this invention can be prepared by altemative 30 methods. In one method, the in situ method, a graft-polyol intermediate product is first formed by homo- or co-polymçrizing ethylenically unsaturated dicarboxylic anhydride monomers in situ in a polyoxy-alkylene polyether polyol followed by an esterification reaction to produce a dispersant. In the other method, the blend method, a homo-35 polymer or copolyrner containing anhydr~de groups is separately 2~ 4 prepared and blended with a polyoxyalkylene polyether polyol. Theresulting blend is converted into the dispersant by an esterification reaction.
In one embodiment, the dispersant of of ehe present invention uses S an ethylenically unsaturated dicarboxylic acid anhydride monomer having a formula ~rom the following group:
R R R R ~CH
~ ~ L r~

oJ`o ~o, ~o~o and O~o~O
where each R group is independently hydrogen or lower alkyl, where lower alkyl is defimed as Cl to C4, where R is preferably methyl if it is 10 an alkyl group. Lower aLtcyl is defined as a straight or branched allcyl group having from 1 to 6 carbon atoms, preferably 1 to 4. These monomers are sometimes re~erred to as Cl-C20 anhydride monomers, as ~e maximum number of carbons for the monomers is 20. Sui~able specific monomers include, but are not limited to maleic anhydride;
15 crotonic anhydride; itaconic anhydride; citraconic anhydride, 2,3-dimethyl maleic anhydride; acrylic anhydride; methacrylic anhydride;
propyl succinic anhydride; derivatives thereof; and mixtures thereof.
Other monomers may be polymerized with the anhydride containing monomers within the scope of this invention. In one aspect of the 20 invention, maleic anhydride is a preferred anhydride monomer of the invention.
For example, one type of dispersant may be prepared from the reaction of polyols with styrene/maleic anhydride (SMA) resins.
Especially preferred are the SMA resins which have been partially 25 esterified ~cause they exhibit high solubility in the polyol. Examples of these resins are SMA 1440, SMA 17352 and SMA 2625 sold commer-cially by the Sartomer division of Atochem. The reaction is accom-plished by simply heating a mixture of the SMA resin, in a proportion ranging from about 2 to 10 wt.%, and the polyol to 180C. for 1.5 30 hours to obtain esterification. Alternatively, this type of dispersant has 2~8017~
been prepared from the polyrnerization of styrene and maleic anhydride in situ in a polyol followed by es~erification.
Since the anhydride containing polymer may be a homopolymer, it iS obvious that 100% of the polymer may be denved from anhydride 5 monomer. At a minimum, in one non-limiting embodiment, at least 1 wt.% of the copolymer should be derived from the anhydride monomer.
There are several advantages of this type of dispersant. It is based on existing, readily available materials, and does not require a speciaI
10 reactor. The procedure is relatively simple and does not require a catalyst and hence removal of such catalyst from a viscous product.
As noted, the unsaturated anhydride may be homopolymerized or copolymerized. While styrene is a preferred comonomer in some instances, other suitable comonomers include, but are not limited to, 15 butadiene, isoprene, I,4-pentadiene, I,6-hexadiene, 1,7-octadiene, styrene, acrylonitrile, methacrylonitrile, oc-methylstyrene, methylsty-rene, 2,4-dimethylstyrene, ethyl styrene, isopropylstyrene, butylstyrene, substituted styrenes, such as cyanostyrene, phenylstyrene, cyclohexylsty~
rene, benzylstyrene, substituted styrenes such as cyanostyrene, nitrosty-20 rene, N,N-dimethylaminostyrene, acetoxystyrene, methyl 4-vinylbenzo-ate, phenoxystyrene, p-vinyl diphenyl sulfide, p-vinylphenyl phenyl oxide, acrylic and substituted acrylic monomers such as acrylic acid, methacrylic acid, methyl acrylate, 2-hydrGxyethyl acrylate, 2-hydroxy-ethyl methacrylate, methyl methacrylate, cyclohexyl methacrylate, 25 benzyl methacrylate, isopropyl methacrylate, octyl methacrylate, ethyl a-ethoxyacrylate, methyl a-acetoaminoacrylate, butyl acrylate, 2-ethylhexyl acrylate, phenyl acrylate, phenyl methaclylate, N,N-dimethylacrylarnide, N,N-dibenzylacrylamide, N-bu~ylacrylamide, rnethacrylyl folmamide, vinyl esters, vinyl ethers, vinyl ke~ones, vinyl 30 acetate, vinyl alcohol, vinyl butyrate, isopropenylacetate, vinyl formate, vinyl acrylate, vinyl methacrylate, vinyl methoxy acetate, vinyl benzo-ate, vinyl toluene, vinyl naphthalene, vinyl methyl ether, vinyl ethyl ether, vinyl propyl ethers, vinyl bu~yl ethers, vinyl 2-ethylhexyl ether, vinyl phenyl ether, vinyl 2-methoxyethyl ether, methoxybutadiene, 35 vinyl 2-butoxye~hyl ether, 3,4-dihydro-1,2-pyran, 2-butoxy-2'-vinyloxy 208~17~

diethyl ether, vinyl 2-ethylmercaptoethyl ether, vinyl methyl ketone, vinyl ethyl ketone, vinyl phenyl ketone, vinyl ethyl sulfide, vinyl ethyl sulfone, N-methyl-N-vinyl acetamide, N-vinylpyrrolidone, vinyl imida~ole, divinyl sulfide, divinyl sulfoxide, divinyl sulfone, sodium 5 vinyl sulfonate, methyl vinyl sulfonate, N-vinyl pyrrole, dimethyl fumarate, dimethyl maleate, maleic acid, crotonic acid, fumaric acid, itaconic acid, monomethyl itaconate, t-butylaminoethyl methacrylate, dimethylaminoethyl methacrylate, gIycidyl acrylate, allyl alcohol, glycol monoesters of itaconic acid, vinyl pylidine, maleic anhydr~de, maleim-10 ide, N-substituted maleimides, such as N-phenylrnaleimide and the like.
The polyol may be a polyoxyalkylene polyether polyol have a molecular weight of from about 500 to 15,000, preferabIy from about 2000 to 10,000. These polyols are typically made by the reac~ion of an initiator or starting material having a pluraIity of reactive hydrogens 15 thereon with one or more allcylene oxides. Ethylene oxide, propylene oxide, butylene oxide and mixtures of these may be used. Often, a mixture of ethylene oxide and propylene oxide is pr~ferred. The result-ing polyols should have predominantly primary hydroxyl groups. While secondary hydroxyl groups are permissible, as secondary hydroxyl 20 groups tend to predominate, the need fior a catalyst to promote the reaction increases, and this is undesirable as described earlier. Addition-ally, the resultant polyols do not contain any induced unsaturation, and should not be compared with such materials. The reaction of the polyol with the anhydride polymer results in a product with no r~sultant 2S unsaturation.
Suitable starting materials or initiators for the polyol include, but are not limited to, di, tri- or tetra-hydric initiators, such as glycerin, alkanolamines, alkylamines, aryl or aromatic amines, sucrose, sorbitol, trimethylol propane (TMP) a-methylglucoside, ~-methylglucoside or 3¢ other methylglucoside, resins of phenol, aniline and mixed phenol aniline, such as methylenedianiline or bisphenol A, Mannich condensates and mixtures thereof, for example. The first or second polyol may be made by alkoxylating the initiator with a desired number of moles of an alkylene oxide. Preferably, the alkylene oxide has two to ~our carbon 35 atoms, and is thus ethylene oxide, propylene oxide, butylene oxide or 2~17~

mixtures of these oxides. The oxides may be mixed upon addition, or may be added to the polyol initiator chain separately to form blocks or caps. In a preferred aspect, a mixture of ethylene oxide and propylene oxide are added to the initiator. The allcoxylation may or may not be catalyzed; KOH is a commonly used catalyst, although others may be employed. For example, double metal cyanide catalysts may be employed, in par~icular zinc hexacyanocobaltate, and the polyols may be prepared in accordance with the methods described in U.S. Pat. Nos.
3,029,505; 3,900,518; 3,941,04~ and 4,355,100, incorporated by reference herein.
As noted, the preparation of the dispersants is quite versatile. In the in situ method described above, the anhydride graft-polymer intermediate can be prepared by polymerizing any suitable anhydri~e monomer or monomer mixture. Suitable anhydride monomers are described above. The anhydride monomer or monomer mixture is then polymerized in situ in a suitable polyol, such as those described above.
Accordingly the anhydride monomer and polymer must be soluble in the polyol. A solvent may be used to dissolve the monomer and polymer.
In one embodiment of this invention, the polyanhydride graft-polyol intermediate will be formed by polymerizing from about S to about 90 total weight percent, preferably from about 20 to about 50 total weight percent, of at least one anhydride monomer ;n a polyoxy-alkylene polyether polyol at a reac~ion temperature within the range of from about 60 to about 150C. The polymerization process may be batch, semi-batch or continuous. Suitable initiators and concentrations are the same as those described later for polymer polyols. The resulting intermediate product formed a single phase, homogeneous liquid, which then must undergo an esterification reaction to form the dispersant of this invention.
In another embodiment pertaining to the blend method for form-ing a polyol polyanhydride-derived dispersant, an anhydride homopoly-mer or copolymer can be used. Particularly suitable for use are the homopolymers and copolymers of the anhydride monomers listed above as being suitable for use in the in sit~ method for forming the disper-9 2 0 ~

sant. The anhydride homopolymer or copolymer is then blended with one or more polyoxyaL~cylene polyether polyols as described above to give a blended intermediate product which upon esterification gives a polyol polyanhydride-derived dispersant of this invention. The blended S intermediate product will be formed to contain from about 1 to about 50 weight percent anhydride polymer, preferably from about 1 to about 20~ with the balance being polyol.
The formation of the dispersant from either intermediate product requires a further esterification reaction, typically, but not necessarily, 10 carried out in additional polyoxyaLkylene polyether polyol in the absence of a catalyst. The polyol, if added, may be the same as or different than the polyol used to form the interrnediate. After esterifica-tion, the weight percent anhydride polymer in the dispersant should be from about 0.5 to about 30, preferably from about 1 to about 10.
15 Accordingly, depending upon the weight percent anhydride polymer in the intermediate, it may or may not be desirable to use additional polyol in the esterification reaction. The weight percent anhydride polymer in the dispersant is selected from a number of factors such as the molecu-lar weight and functionality of the polyol and the mole fraction of 20 anhydride groups in the polymer. In general, higher molecular weight and higher functionality polyols require a lower level of anhydride polymer level. Too high a level may cause the mixture to gel because of excess crosslinking and should be avoided. The viscosity of the disper-sant is preferably less than 30,000 cps at 25C. The esterification 25 reaction occurs between the terrninal hydroxyl groups of the polyol and the anhydride groups of the anhydride polymer. From about 1 to about 100 mole percen~, preferably all of the ~otal anhydride groups of the anhydride polymer react with the hydroxyl groups of the polyol.
The esterification reaction is accomplished by allowing the polyol 30 and anhydride polymer to react at a tempera~ure of from about 150 to 190C. for about 1.5 to 3 hours. The times and temperatures specified above are exemplary but not required. Catalysts may be added to accelerate the reaction permitting use of lower temperatures and shorter reaction times. Suitable catalysts are well known in the art. The esreri-35 fication reaction produces a material which contains a significant 2o8ol74 amount of high molecular weight adducts. The esterification reactionalso produces small amounts of carboxylic acid groups. Generally the small amount of acidity present in the dispersant and the low dispersant level present in the polymer polyol does not affect urethane catalysis. If 5 required, the residual acidity may be neutralized by any common technique. For example, additional aLIcylene oxide could be added.
The polymer polyols of this invention will be fonned by polymerizing an ethylenically unsaturated monomer or mixture of monomers in a polyol mixture comprising at least one polyoxyalkylene l0 polyol and the dispersant in the presence of a free radical initiator at a temperature from about 60C. to about 150C~.
Any conventional process for preparing polymer polyols can be employed including batch, semi-batch, and continuous processes. The preferred process is a semi-batch process in which all or at least a major 15 amount of the dispersant is added in the reactor charge and the major amount of polyol is added in ~e feed charge. It is most pre~erred to add all of the dispersant in the reactor charge. If a plurality of continuous stirred tank reactors ~CSl~Rs) in scries is employed, the charge to the first CSTR preferably includes all or at least the major amount of 20 dispersant. To the second CSTR, in addition to the product feed from the first CSTR, will be added the feed charge containing the major amount of polyol.
The amount of the dispersant employed to produce the polymer polyol will be within the weight percent range of from about 0.1 to 25 about 30, preferably from about 1 to about 15 based on the total amount of monomer, polyol and dispersant employed. The weight ratio of total monomer or monomer mixture (or disperse phase) to polyol (or continuous phase) wilI be from about 1:19 to about 1:1.
The preferred ethylenically unsatu~ated monomers employed to 30 produce polymer polyols of the present invention are both styrene and acrylonitrile to make a copolymer. The copolymer will contain in weight percent 20 to 100 styrene with the ba}ance being acrylonitrile.
Other suitable monomers include, but are not limited to, butadiene;
isoprene; 1,4-pentadiene; 1,6-hexadiene, 1,7 octadiene; acrylonitrile;
35 methacrylonitrile; a-methyl styrene; me~hylstyrene; 2,4-dimethylsty-20~17~
rene; ethyl styrene; isopropylstyrene; butylstyrene; substituted styrenessuch as cyanostyrene; phenylstyrene; cyclohexylstyrene; benzylstyrene;
cyanostyrene; nitrostyrene; N,N-dimethylaminostyrene; acetoxystyrene;
methyl 4-vinylbenzoate; phenoxystyrene; p-vinyl diphenyl sulfide; p-S vinylphenyl phenyl oxide; acrylic and substituted acrylic monomerssuch as acrylic acid; methacrylic acid; methyl ac~ylate; 2-hydroxyethyl acrylate; 2-hydroxyethyl methacrylate; methyl methacrylate; cyclohexyl methacrylate; benzyl methacrylate; isopropyl methacrylate; octyl me~h-acrylate; ethyl o~-ethoxyacrylate; methyl a-acetoaminoacryIate; butyl 10 acrylate; 2-ethylhexyl acrylate; phenyl acrylate, phenyl me~hacrylate;
N,N-dimethylacrylate; N,N-dibenzylacrylamide; N-butylacrylamide;
me~hacrylyl fonnamide; vinyl esters; vinyl ethers; vinyl ketones; vinyl ace~ate; vinyl alcohol; vinyl butyrate; isopropenylacetate; vinyl formate;
vinyl acrylate; vinyl methacrylate; vinyl methoxy acetate; vinyl 15 benzoate; vinyl toluene; vinyl naphthalene; vinyl methyI ether; vinyl ethyl ether; vinyl propyl ethers; vinyl butyl ethers; vinyl 2-ethylhexyl ether; vinyl phenyl ether; vinyl 2-methoxyethyl ether; methoxybuta-diene; vinyl 2-butoxyethyl ether; 3,4-dihydro-1,2-pyran; 2-butoxy-2'-vinyl diethyl ether; vinyl 2-ethylrner-captoethyl ether; vinyl methyl 20 ketone; vinyl ether ketone; vinyl phenyl ketone; vinyl ethyl sufide; vinyl ethyl sulfone; N-methyl-N-vinyl acetamide; N-vinylpyrrolidone; vinyl imidazole; divinyl sulfide; divinyl sulfoxide; divinyl sulfone; sodium vinyl suI~onate; methyl vinyl sulfonate; N-vinyl pyrrole; dimethyl fumaric; dimethyl maleate; maleic acid; crotonic acid; fumaric acid;
25 itaconic acid; monomethyl itaconate; t-butylaminoethyl methacrylate;
glycidyl acrylate; allyl alcohol; glycol monoesters of itaconic acid; vinyl pyridine; maleic anhydride; maleimide; N-substituted maleimides; such as N-phenylmaleimide and the like.
l'he polymerization initiator for the polymer poIyol preparation 30 may be any suitable initiator for the particular monomers employed.
Suitable catalytic initiators useful in producing ~he polymer polyol compositions of this invention are the free radical type of vinyl polymerization catalysts, such as the peroxides, persulfates, perborates, percarbonates, azo compounds, and the like. Specific examples include, 35 but are not limited to, 2,2'-azo-bis-isobutyronitrile ~AIBN); dibenzoyl 12 2~80174 peroxide; lauroyl peroxide; di-t-butyl peroxide; diisopropyl peroxide carbonate; t-butyl peroxy-~-ethylhexanoate; t-butylperpivalate; 2,5-dimethyl-hexane-2,5-di-per-2-ethyl hexoate; t-butylperneodecanoate; t-butylperbenzoate; t-butyl percrotonate; t-butyl perisobutyrate; di-t-butyl S perphthalate; 2,2'-azo-bis~2-methylbutanenitrile) for example. Other suitable catalysts may be employed, of course. The concentration of initiator is not cr~tical and can vary within wide limits of from about 0.1 to about 5.0 weight percent based on the ~otal feed to the reactor. A
chain transfer agent such as dodeeylmercaptan may also be added.
The polyols most suitable for use in the polymer polyols of this invention (sometimes called the first polyoxyalkylene polyether polyo~l) are polyoxyaLkylene polyether polyols or mixtures ~ereof which are the polymerization products of an aLIcylene oxide or a mixture of alkylene oxides with a polyhydric alcohol, as described above. The 15 polyol may contain small amounts of unsaturation, but unsaturation is not intentionally added according to the invèntion. The moIecular weight of the polyol will be within the range of from about 500 to about 15,000, pr~ferably from about 2,000 to about 10,000. Although typically the polyols selected for the preparation of the intermediate, the 2û esterification reaction and the polymer polyol will be iden~ical, they may all be different polyoxyallcylene polyether polyols. As discussed above, depending on the weight percent anhydride polymer in the intermediate, a third addition of polyo~ may not be required.
Polymer polyols according to this invention will be ~ormed by 25 polymerizing from about S to less than about 50 weight percent, preferably 10 to 45 weight percent, of ~he ethylenically unsaturated monomer or monomer mixture, based on the total weight of the monomer and polyol, in from about 95 to about 50 or more weight percent, preferably about 90 to about 55 weight percent, of at least one 30 polyoxyalkylene polye~her polyol in the presence of a dispersant of the invention.
The intermediates, dispersants, and polymer polyols using the dispersants, and polyurethanes using the polymer polyols of the invention will be further illustrated with reference to the following 13 2~017~

examples, which are merely meant to exemplify and not define the invention.

Example 1 Preparation of Dispersant by Reaction of Polyol with A Preformed Resin Containjn~ Anhvdride Group~
Into a reactor fitted with a stirrer, condenser, and thermometer and under a blar~cet of nitrogen were charged 277.5 g. of polyol A and 22.5 g. of SMA 17352 res~n. The contents were heated to 180C., held at ~at temperature for 2 hours, and allowed to cool. The viscosity of the product was 9300 cps.
Example 2 Example 1 was repea~ed with 285 g. of polyol B and 15 g. of SMA 17352 resin. The viscosity of the product was 15,000 cps.
~ .
Preparation of Dispersant by Reaction of Pol-/ol with Polymaleic Anhvdride Example 1 was repeated with 96.5 g. of polyol D and 3 5 g of polymaleic anhydride resin (available from Polysc}ences Inc.). The viscosity of the product was S,230 cps.

Example 4 Preparation of Dispersant by Polymerizing Monorners in a Polyol FollQwed ~ Reaçtion of ~he Polvol wit~nhvd~id~;;rQu~s Into a reactor fitted with a stirrer, condenser, addition tube and thermometer and under a blanket of nitrogen were charged 200 g. of polyol D. After heating the reactor charge to 120C., the feed charge was added over a 2 hour period at 120C. IJpon completion of the addition, the reaction product was held at temperature for 0.5 hours, then stripped of residual monomers ~or 1.5 hours at 11$-120C. and < S
mm Hg. The contents were then heated to 180C. for 2 hours under nitrogen and then allowed to cool. The viscosity of the product was 22,700 cps. The feed charge was as shown below, in grams:

. ~ ~
-.: .,. ` '; . , ~. ..
:

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Methacrylic anhydride 20 Butyl acrylate 80 Vazo 67'~) initiator lO
Polyol D 700 Examples S through 8, sumrnarized in Table I, illustrate the preparation and properties of polymer polyols made using the dispersants from Examples 1 through 4.
s Procedures for Measurements ~f Phvsi~al ~bL~m~
Viscosity was measured using a Brookfield cone and plate viscometer, Spindle ~CP-52, operated at 20 secs-l at 25C.
Particle sizes were measured using a Coulter N4 Particle Size Analyzer with o-xylene or isopropyl alcohol as the dispersing media.
Centrifugable solids were detemlined by centrifuging a sample of the polymer polyol for about 24 hours at about 3300 Ipm and 1470 radial cen~rifugal "g" forces. The centrifuge tube was then inverted and allowed to drain for 4 hours. The non-flowing cake at the bottom of the tube is reported as weight percent of the initial weight of the sample tested.

Preparation of Polvrne~PolvQls Into a reactor fitted with a stirrer, condenser, thermometer and addition tube and under a blanket of nitrogen were charged the amounts of reactants indicated in Table I. After heating the reactor charge to the reaction temperature, the feed charge was added over the indicated time period. Upon completion of the addition, the reaction product was held at the reaction temperature for 0.5 to 1.0 hours, then stripped of residual monomers for 1.0 hour at 115-125C. and < S mm Hg.

.
.

, ~108~17~

Table I
Preparation of PolYmer Polvols Example No. 5 6 7 8 Monomer charge, wt.% 35 30 40 25 S/AN Ratio 75/25 75/25 75/25 70/30 E3ase Polyol C A C C
Dispersant from Ex. 1 2 4 3 Reaction Temp., C. 120 1~0 120 120 Feed addition time, hrs. 2 2 2 Feed~ ~
Styrene 525 450 600 350 Acrylonitrile 175 150 200 150 Vazo 67~ 12 10 18 12 Basepolyol 1131 1050 880 1050 Rçactor char~e.~
Base polyol 117 280 284 39Q
Dispersant 52 70 36 60 Viscosity, cps. 20/sec.2800 3580 5490 1810 Particle Size"u 0.68 0.61 0.59 0.69 Cen~ifugable solids, wt.%3.1 2.4 4.0 2.9 S From the above data, it will be seen that ~e dispersants of this invention are effective in achieving stable dispersions at high solids contents. Moreover, the particle sizes, viscosities and centrifugable solids of the polymer polyols produced using the dispersants are excellent. It is anticipated further that polymer polyols employing the dispersants of the present invention will find utility as coreactants with polyisocyanates in the presence of a suitable polyurethane catalyst to produce polyurethane foams.

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Preparation of Polvurethane Foams Polyurethanes may be made by reacting the polymer polyols described above with an organic polyisocyanate in the presence of a polyurethane forma~ion catalyst. If a foam is. desired, a blowing agent S such as a halocarbon (trichlorofluoromethane, for example), water, or carbon dioxide may also be present. The polyurethane formation catalysts are typically tin catalysts or tertiary amine compounds. Other conventional additives such as silicone surfactants, fire retardant addi-tives (melamine~ for exarnple), etc. may also be present. For more 10 information in preparing polyurethanes, particularly flexible polyure-thanes, see U.S. Pat. Nos. 4,338,408; 4,3~2,687 and 4,38k353, incorporated by reference herein. The foams made using the polymer polyols described herein have excellent physical properties. Flexible carpet underlay foam and molded automobile foam may be prepared 15 using the polymer polyols and techniques described herein.
A typical slab polyurethane foam is prepared by first charging polymer polyol, water, catalyst and silicone surfactant into a vessel while stirring vigorously. Next, the polyisacyanate is added to the vessel with stirring, and the resulting mixture is immediately poured into a 20 cardboard cakebox; and the polyurethane foam is allowed to rise and cure at room temperature.
The polyurethane foams were separately prepared by charging the amounts of polymer polyol, water, catalysts and silicone surfactant indicated into a one-liter cylindrical container equipped with a 25 mechanical stirrer. The mixture was stirred for about 10 seconds at about 2500 rpm and the indicated amount of polyisocyanate was introduced into the container with stirring for about S seconds. The contents of the container were then irnmediately poured into a cardboard cake box and the foam was allowed to rise. After ~e foam 30 rise was completed, the foam was allowed to cure at room temperature for about one day.

` ~ , , -17 2~17'~

Example 9 Prçpara~ion of Polvurethane Foam Using the procedure described above, the following carpet underlay folmulation was used to prepare a polyurethane foarn:
s Polymer polyol of Example 5 100 Water 2.2 L-6202l 0.8 Amine2 0-3 T-10 Catalyst (50% active)3 0.4 TDI 29.6 The foarn reactivity was acceptable and the resulting foam showed 15 the expected physical properties.
Many modifications may be made in the dispersan~s of this invention and their method of production without departing from the spint and scope of ~e invention, which are de~lned only in the appended claims. For example, one skilled in the art could adjust the 20 temperature, pressure, reactants, proportions and modes of addi~ion wi~in the parameters se~ forth to provide dispersants with particularly advantageous properties. Monomers and combinations of monomers other ~han those explicitly recited are an~icipated as useful herein.

~LO~SARY

Polyol A (ARCOL~) 1342 polyol) A glycerin started polyether of propylene oxide and ethylene oxide Contain1ng 14 wt.% ethylene oxide having a hydroxyl number of 34 and a primary hydroxyl I Silicone surfactaot, produc~ of Union Carbide Corporation.
2 Prepared from 2 parts Bl I and I part 33LV, both of which are products of Air Products and Chemicals, Inc. and 3 par~s Thanol~9 F-3020, a product of ARCO Chemical Company.3 Organo tin catalyst, available from Air Products and Chemicals, Inc.

, . .
. .
, 18 208~17~

group conten~ of 80% of the total hydroxyl content made by ARCO Chemical Co.
Polyol B A glycerin started polyether of propylene oxide S and ethylene oxide containing 15 w~.% ethylene oxide with a hydroxyl number of 16 and a pnmary hydroxyl group content of 80% of the total hydroxyl conten~.
Polyol C (ARCOL(9 1131 polyol) A glycerin started polyether of propylene oxide and ethylene oxide conta~ning 12% random ethylene oxide having a hydroxyl num~er of 48 made by ARCO Chemical Co.
Polyol D A glycerin started polyeth~r of propylene oxide and ethylene oxide containing 14 wt.% ethylene oxide with a hydroxyl number of 26 and a primary hydroxyl group content of 80% of the total hydroxyl content.

SMA 17352 A partially estenfied styrene maleic anhydride polymer copolymer resin~ sold by the Sartomer division of Atochem.
Vazo~) 67 2,2'-Azobis(2-methylbutanenitrile) polymeriza-tion catalyst made by E.I. duPon~ de Nemours and Co.

.' ' , : ,

Claims

Claims We Claim:

1. A stable polymer polyol composition comprising a continuous phase, a disperse phase within the continuous phase, and a dispersant for enhancing the stability of the polymer polyol, wherein (a) the disperse phase consists essentially of vinyl polymer particles;
(b) the continuous phase consists essentially of a first polyoxyalkylene polyether polyol; and (c) a dispersant produced by the process comprising:
(1) polymerizing from about 1 to about 50 weight percent of at least one anhydride monomer selected from the group consisting of C1-C20 anhydride monomers in from about 99 to about 50 weight percent of a second polyoxyalkylene polyether polyol to form a single phase homogeneous liquid intermediate reaction product followed by (2) esterifying from about 1 to about 100 mole percent of the total anhydride groups in the intermediate reaction product with the hydroxyl groups of the second polyoxyalkylene polyether polyol to form the dispersant;
said dispersant being employed in an amount sufficient to enhance the stability of the resulting polymer polyol as compared to the stability of the polymer polyol in the absence of the dispersant.

2. The polymer polyol composition of claim 1 where the anhydride monomer has a formula selected from the group consisting of:

, , and where each R group is independently H, lower alkyl or phenyl and x is an integer from 0 to 6.

3. The polymer polyol composition of claim 1 where the anhydride monomer is selected from the group consisting of maleic anhydride;
crotonic anhydride; itaconic anhydride; citraconic anhydride; 2,3-dimethyl maleic anhydride; acrylic anhydride; methacrylic anhydride;
propyl succinic anhydride; derivatives thereof; and mixtures thereof.

4. The polymer polyol composition of claim 1 where the first and second polyoxyalkylene polyether polyols have a molecular weight within the range of from about 500 to about 15,000.

5. The polymer polyol composition of claim 1 where the anhydride monomer is co-polymerized with at least one other ethylenically unsaturated comonomer.

6. The polymer polyol composition of claim 5 where the comonomer is styrene.

7. The polymer polyol composition of claim 1 in which said dispersant (c) is formed by polymerizing from about 20 to about 50 weight percent of the at least one anhydride monomer in from about 80 to about 50 weight percent of the polyol.

8. The polymer polyol composition of claim 1 in which said dispersant (c) is employed in an amount within the range of from about 0.1 to about 30 weight percent based on the total weight of (a)+(b)+
(c).

9. The polymer polyol composition of claim 1 in which said dispersant (c) is employed in an amount within the range of from about 1 to about 15 weight percent based on the total weight of (a) + (b) + (c).

10. The polymer polyol composition of claim 1 in which the weight ratio of the disperse phase (a) to the continuous phase (b) is within the range of from about 1:19 to about 1:1.

11. The polymer polyol composition of claim 1 in which said first and second polyoxyalkylene polyether polyols have the same composition.

12. The polymer polyol composition of claim 1 in which said first and second polyoxyalkylene polyether polyols have different compositions.

13. The polymer polyol composition of claim 1 in which an additional second polyoxyalkylene polyether polyol or a third polyoxyalkylene polyol is added to dilute the anhydride just prior to esterifying.

14. A stable polymer polyol composition comprising a continuous phase, a disperse phase within the continuous phase, and a dispersant for enhancing the stability of the polymer polyol, wherein (a) the disperse phase consists essentially of vinyl polymer particles;
(b) the continuous phase consists essentially of a first polyoxyalkylene polyether polyol; and (c) a dispersant produced by the process comprising:
(1) polymerizing from about 1 to about 50 weight percent of at least one anhydride monomer selected from the group consisting of homopolymers and copolymers of C1-C20 anhydride monomers having a formula selected from the group consisting of:

, and where each R group is independently H, lower alkyl or phenyl and x is an integer from 0 to 6, in from about 99 to about 50 weight percent of a second polyoxyalkylene polyether polyol to form a single phase homogeneous liquid intermediate reaction product followed by (2) esterifying from about 1 to about 100 mole percent of the total anhydride groups in the intermediate reaction product with the hydroxyl groups of the second polyoxyalkylene polyether polyol to form the dispersant;
said dispersant being employed in an amount sufficient to enhance the stability of the resulting polymer polyol as compared to the stability of the polymer polyol in the absence of the dispersant, and where the first and second polyoxyalkylene polyether polyols have a molecular weight within the range of from about 500 to about 15,000.

15. The polymer polyol composition of claim 14 where the anhydride monomer is selected from the group consisting of maleic anhydride;
crotonic anhydride; itaconic anhydride; citraconic anhydride; 2,3-dimethyl maleic anhydride; acrylic anhydride; methacrylic anhydride;
propyl succinic anhydride; derivatives thereof; and mixtures thereof.

16. The polymer polyol composition of claim 14 where the anhydride monomer is co-polymerized with at least one other ethylenically unsaturated comonomer.

17. The polymer polyol composition of claim 16 where the comonomer is styrene.

18. The polymer polyol composition of claim 14 in which said dispersant (c) is formed by polymerizing from about 20 to about 50 weight percent of the at least one anhydride monomer in from about 80 to about 50 weight percent of the polyol.

19. The polymer polyol composition of claim 14 in which said dispersant (c) is employed in an amount within the range of from about 0.1 to about 30 weight percent based on the total weight of (a) + (b) +
(c).

20. The polymer polyol composition of claim 14 in which the weight ratio of the disperse phase (a) to the continuous phase (b) is within the range of from about 1:19 to about 1:1.

21. The polymer polyol composition of claim 14 in which an additional second polyoxyalkylene polyether polyol or a third polyoxyalkylene polyol is added to dilute the anhydride just prior to esterifying.

22. The polymer polyol composition of claim 14 in which said disperse phase is polystyrene particles.

23. The polymer polyol composition of claim 14 in which said disperse phase is styrene/acrylonitrile copolymer particles.

24. The polymer polyol composition of claim 14 in which said disperse phase is styrene/N-phenylmaleimide copolymer particles.

25. The polymer polyol composition of claim 14 in which said disperse phase is styrene/N-phenylmaleimide/acrylonitrile copolymer particles.

26. The polymer polyol composition of claim 14 in which said continuous phase is a polyoxyalkylene polyether polyol having a molecular weight within the range of from about 2,000 to about 10,000.

27. A method for producing the stable polymer polyol of claim 15 which comprises polymerizing an ethylenically unsaturated monomer or mixture of monomers to form the vinyl polymer particles in a blend of the first polyoxyalkylene polyether polyol and the dispersant.

28. A method for producing the stable polymer polyol of claim 14 which comprises polymerizing an ethylenically unsaturated monomer or mixture of monomers to form the vinyl polymer particles in a blend of the first polyoxyalkylene polyether polyol and the dispersant.

29. A method of stabilizing a polymer polyol comprising vinyl polymer particles dispersed in a continuous polyether polyol phase against phase separation, the method comprising incorporating into the polymer polyol composition a dispersant formed by polymerizing from about 1 to about 50 weight percent of at least one anhydride monomer selected from the group consisting of C1-C20 anhydride monomers in from about 99 to about 50 weight percent of a polyoxyalkylene polyether polyol to form a single phase homogeneous liquid intermediate reaction product followed by esterifying from about 1 to about 100 mole percent of the total anhydride groups in the intermediate reaction product with the hydroxyl groups of the polyoxyalkylene polyether polyol to form the dispersant.

30. A method of stabilizing a polymer polyol comprising vinyl polymer particles dispersed in a continuous polyether polyol phase against phase separation, the method comprising incorporating into the polymer polyol composition a dispersant formed by polymerizing from about 1 to about 50 weight percent of at least one anhydride monomer selected from the group consisting of homopolymers and copolymers of C1-C20 anhydride monomers in from about 99 to about 50 weight percent of a polyoxyalkylene polyether polyol to form a single phase homogeneous liquid intermediate reaction product followed by esterifying from about 1 to about 100 mole percent of the total anhydride groups in the intermediate reaction product with the hydroxyl groups of the polyoxyalkylene polyether polyol to form the dispersant.

31. A dispersant produced by the process comprising:
polymerizing at least one anhydride monomer selected from the group consisting of C1-C20 anhydride monomers to form a polymer followed by esterifying from about 1 to about 100 mole percent of the total anhydride groups in the polymer with hydroxyl groups of an polyoxyalkylene polyether polyol to form the dispersant.

32. The dispersant of claim 31 where the polymerization of the anhydride monomer occurs prior to mixing the polymer with the polyoxyalkylene polyether polyol and subsequent esterification therewith.

33. The dispersant of claim 31 where the anhydride monomer is mixed with the polyoxyalkylene polyether polyol and is polymerized in situ with the polyoxyalkylene polyether polyol prior to esterification with the polyoxyalkylene polyether polyol.

34. The dispersant of claim 31 where the anhydride monomer has a formula selected from the group consisting of:

, , and where each R group is independently H, lower alkyl or phenyl and x is an integer from 0 to 6.

35. The dispersant of claim 31 where the anhydride monomer is selected from the group consisting of maleic anhydride; crotonic anhydride; itaconic anhydride; citraconic anhydride; 2,3-dimethyl maleic anhydride; acrylic anhydride; methacrylic anhydride; propyl succinic anhydride; derivatives thereof; and mixtures thereof.

36. The dispersant of claim 31 where the polyoxyalkylene polyether polyol has a molecular weight within the range of from about 500 to about 15,000.

37. The dispersant of claim 31 where the anhydride monomer is co-polymerized with at least one other ethylenically unsaturated comonomer.

38. The dispersant of claim 37 where the comonomer is styrene.

39. A dispersant produced by the process comprising:
polymerizing from about 1 to about 50 weight percent of at least one anhydride monomer selected from the group consisting of C1-C20 anhydride monomers in from about 99 to about 50 weight percent of a polyoxyalkylene polyether polyol to form a single phase homogeneous liquid intermediate reaction product followed by esterifying from about 1 to about 100 mole percent of the total anhydride groups in the intermediate reaction product with the hydroxyl groups of the polyoxyalkylene polyether product to form the dispersant.

40. The dispersant of claim 39 where the anhydride monomer has a formula selected from the group consisting of:

, , and where each R group is independently H, lower alkyl or phenyl and x is an integer from 0 to 6.

41. The dispersant of claim 39 where the anhydride monomer is selected from the group consisting of maleic anhydride; crotonic anhydride; itaconic anhydride; citraconic anhydride; 2,3-dimethyl maleic anhydride; acrylic anhydride; methacrylic anhydride; propyl succinic anhydride; derivatives thereof; and mixtures thereof.

42. The dispersant of claim 39 where the polyoxyalkylene polyether polyol has a molecular weight within the range of from about 500 to about 15,000.

43. The dispersant of claim 39 where the anhydride monomer is co-polymerized with at least one other ethylenically unsaturated comonomer.

44. The dispersant of claim 43 where the comonomer is styrene.

45. A polyurethane foam composition comprising the reaction product of a polymer polyol with a polyisocyanate in the presence of a polyurethane catalyst, where the polymer polyol is produced by a process comprising polymerizing, via a free-radical reaction, an addition polymerizable monomer with ethylenic unsaturation in the presence of a base polyol and a dispersant, and where the dispersant is produced by a process comprising:
polymerizing at least one anhydride monomer selected from the group consisting of C1-C20 anhydride monomers to form a polymer followed by esterifying from about 1 to about 100 mole percent of the total anhydride groups in the polymer with hydroxyl groups of an polyoxyalkylene polyether polyol to form the dispersant.

46. A polyurethane product made by a process comprising reacting a polymer polyol of claim 1 with an organic polyisocyanate in the presence of a polyurethane catalyst.